The present invention relates to the field of latches of the type particularly adaptable for joining and securing two adjacent and generally planar members. More particularly the invention pertains to an over center or toggle type latch including a separate drawhook and activating handle operatively attached to a base and additionally having means to adjust the latch tension and means to secure the latch in a fully closed position against accidental opening.
Latches of this general construction and including the various features described above are well-known in the art. For example, U.S. Pat. No. 3,936,082 discloses an overcenter tension latch with an anti-release or secondary locking mechanism. Also disclosed therein are means for varying the tension in the latch. However, the secondary lock is activated by the same general motion employed in raising the handle since it operates generally in the same direction as the movement of the handle. Also, the adjustment means is not readily accessible when the latch is in the closed position and, as a result, tension adjustments must be made in an open position with trial and error methods employed to reach the proper tension. U.S. Pat. No. 3,237,978 discloses a similar type of latch, including a secondary locking mechanism and a tension adjustment means. Again, however, the secondary locking means operates in the same direction as handle movement when the latter is lifted to open the latch. Such unidirectional movement of the secondary locking mechanism and the handle itself inhibits the efficacy of the device to remain locked against an accidentally applied unidirectional force. The secondary locking mechanisms disclosed in the foregoing patents also occupy substantially greater height above the members to be connected than would ordinarily be required for the remainder of the latch mechanism. As a result, such secondary locking mechanisms detract from the low horizontal profile or "silhouette" of the overall latch.
U.S. Pat. Nos. 3,519,298 and 3,602,723 also disclose latches with secondary locking or anti-release mechanisms. These mechanisms also operate generally in planes perpendicular to the latch bases and protrude substantially above the general horizontal profile of the latches.